200844733 - 九、發明說明： .【發明所屬之技術領域】 本發明涉及一種監控裝置，尤指一種電腦主機板電源之 供電電壓監控裝置及其電壓延遲電路。 【先前技術】 電腦糸統的電源由一次電源與 >一次電源構成。^一次電源 即機箱電源輸出之電源。二次電源即主機板上各個電源轉換 模組輸出之電源。機箱電源輸出之電源電壓有+5V、-5V、 + 12V、-12V、+3.3V等，這些電壓並不能滿足主機板上各個 模組工作所需，因此在主機板上需要增加電源轉換模組將機 箱電源輸出之電壓轉換為主機板各個模組之工作電壓，如 CPU之工作電壓為1.2V，北橋之工作電壓為1.5V與1.2V 等，提供這些工作電壓之電源統稱為二次電源。 主機板製造商在主機板出貨或投入使用之前一般會對 主機板進行功能測試，以保證主機板組成元件功能正常。然 _而，如果從機箱電源輸出的電壓以及主機板電源轉換模組輸 出之電壓不正常時，那麼在功能測試時輕則導致功能測試異 常，重則導致燒毁零件與線路板。例如，如果主機板輸出給 CPU工作之電壓偏高將會導致燒毁CPU，給記憶體與硬碟機 供電之電壓偏高則會燒毀記憶體以及硬碟機，不但造成經濟 上之較大損失，同時也影響產品品質以及生產效率。 【發明内容】 鑒於以上内容，有必要提供一種主機板電壓監控裝置， 在對主機板做功能測試前指不主機板電源提供的電壓是否 6 200844733 ， 正常，並提供一種電壓延遲電路，消除電壓測試中由於電源 . 時序造成之誤判。 一種主機板電壓監控裝置，包括：一電阻和一電位器， 該電阻和電位器串聯於一穩定電壓與地之間，且其間之節點 輸出一基準電壓；一比較器，其包括一正相輸入端、一反相 輸入端、一輸出端及一電源端，該比較器之正相輸入端與該 電阻與電位器間之節點連接，該比較器之反相輸入端與該主 機板電源提供之一電壓連接，當該主機板電源提供之電壓小 ®於該基準電壓時，該比較器之輸出端輸出一控制訊號；一電 子開關，其包括第一、第二與第三端，該電子開關之第一端 與該比較器之輸出端連接，第二端與一參考電壓連接，第三 端接地，當該電子開關之第一端接收該控制訊號時，該電子 開關導通；一發光二極體，其陰極與該電子開關之第二端連 接，其陽極與該參考電壓連接，該電子開關導通時該發光二 極體導通；以及一電壓延遲電路，連接於該參考電壓與該比 ⑩較器之電源端之間，對該參考電壓進行延遲後提供給該比較 器。 一種主機板電壓監控裝置，包括：一電阻和一電位器， 該電阻和電位器串聯於一穩定電壓與地之間，且其間之節點 輸出一基準電壓；一比較器，其包括一正相輸入端、一反相 輸入端、一輸出端及一電源端，該比較器之反相輸入端與該 電阻與電位器間之節點連接，該比較器之正相輸入端與該主 機板電源提供之一電壓連接，當該主機板電源提供之電壓大 於該基準電壓時，該比較器之輸出端輸出一控制訊號；一電 7 200844733 子開關，其包括第一、第二和第三端，該電子開關之第一端 .與該比較器之輸出端連接，第二端與一參考電壓連接，第三 端接地，當該電子開關之第一端接收該控制訊號時，該電子 開關導通；一發光二極體，其陰極與該電子開關之第二端連 接，其陽極與該參考電壓連接，該電子開關導通時該發光二 極體導通；以及一電壓延遲電路，連接於該參考電壓與該比 較器之電源端之間，對該參考電壓進行延遲後提供給該比較 _ 一種電壓延遲電路，其包括一開關、一延遲電阻、一延 遲電容、一放電電阻、一第二電子開關及一第三電子開關， 該開關、延遲電阻及延遲電容依次串聯於該參考電壓與地之 間，該延遲電阻及延遲電容間之節點輸出一驅動電壓，該第 二電子開關之第一端與該節點連接，第二端分別與該參考電 壓與該第三電子開關之第一端連接，第三端接地，該第三電 子開關之第二端與該參考電壓連接，第三端輸出延遲後之參 _考電壓，該放電電阻連接於該節點與地之間，該開關打開後 釋放該延遲電容之電壓。 上述主機板電壓監控裝置在該主機板電源提供之電壓 大於或小於監控人員所設定之基準電壓時使該發光二極體 發光，從而提醒監控人員及時調整主機板電源提供之電壓， 避免異常電壓在功能測試時燒毁價格昂貴之零部件，上述電 壓延遲電路使比較器延遲工作，確保進行比對時地測試電壓 已達到穩定值，消除由電源時序造成之誤判。 【實施方式】 8 200844733 • 請參照圖1，本發明主機板電壓監控裝置之較佳實施方 . 式用於主機板做功能測試前檢測主機板上兩不同電源提供 之電壓11和12是否正常。該主機板電壓監控裝置包括四指 示裝置1〜4、一報警裝置5及一電壓延遲電路6。該等指示 裝置1和2用於指示主機板電源提供之電壓11是否正常， 該等指示裝置3和4用於指示主機板電源提供之電壓12是 否正常，該報警裝置5用於指示主機板電源提供之電壓11 和12是否正常並在主機板電源提供之電壓11、12異常時報 ’警。 該指示裝置1包括電阻R1〜R5、電位器R30、比較器 U1、雙極型電晶體Q1和發光二極體D1。 該電阻R1與電位器1130串聯於一穩定電壓¥1與地之 間，該穩定電壓VI可由機箱電源輸出之一電壓經過穩壓電 路穩壓後獲得。調整該電位器R30，使該電阻R1與電位器 R30間之節點輸出一下限基準電壓，該下限基準電壓爲主機 0板電源提供之電壓11之下限電壓。該比較器U1包括一正相 輸入端、一反相輸入端、一輸出端及一電源端，該比較器 U1之正相輸入端與該電阻R1與電位器R30間之節點連接， 該比較器U1之反相輸入端透過該電阻R2與主機板電源提 供之電壓11連接，該比較器U1之電源端與該電壓延遲電路 6連接。 _ 該電晶體Q1包括第一、第二和第三端（即基極、集極 和射極），該電晶體Q1之第一端透過該電阻R3與該比較器 U1之輸出端連接，第二端透過該電阻R4接入一參考電壓 200844733 • V2,第三端接地。該參考電壓V2爲機箱電源輸出之一電壓。 、 該發光二極體D1之陰極與該電晶體Q1之第二端連接，其 陽極透過該電阻R5與該參考電壓V2連接。 該電壓延遲電路6包括一開關S、一延遲電阻R21、一 延遲電容C、一 N通道場效電晶體Q7及一 P通道場效電晶 體Q8，該開關S、延遲電阻R21及延遲電容C依次串聯於 該參考電壓V2與地之間，該延遲電阻R21及延遲電容C間 之節點輸出一驅動電壓，一放電電阻R22連接於該節點與地 之間；該場效電晶體Q7之第一端（閘極）與該節點連接， 該場效電晶體Q 7之弟二端（>及極）透過一電阻R23與該爹 考電壓V2連接以及與該場效電晶體Q8之第一端（閘極） 連接，該場效電晶體Q7之第三端（源極）接地；該場效電 晶體Q8之第二端（源極）與該參考電壓V2連接，該場效 電晶體Q8之第三端（汲極）與該比較器U1之電源端連接。 閉合開關S後，當該延遲電容C之電壓上升到一定值時該場 效電晶體Q 7導通’進而使該場效電晶體Q 8導通。 當該主機板電源提供之電壓11大於該下限基準電壓 時，該比較器U1之輸出端輸出一低電平訊號，該電晶體Q1 之第一端接收該低電平訊號，故該電晶體Q1截止，從而該 發光二極體D1無電流流過而不發光。當該主機板電源提供 之電壓11小於該下限基準電壓時，該比較器U1之輸出端輸 出一高電平之控制訊號，該電晶體Q1之第一端接收該控制 訊號，故該電晶體Q1之第二端與第三端導通，從而該發光 二極體D1有電流流過而發出紅色光’指不該主機板電源提 200844733 • 供之電壓11異常。 . 由於主機板電源存在時序問題，因此在進行電壓檢测時 會因主機板電源提供之電壓11未達到穩定值而小於該下限 基準電壓之情況發生，因此該電壓延遲電路6對參考電壓 V2延遲後再輸出到該比較器U1，確保該比較器U1工作時 該主機板電源提供之電壓11已經達到穩定值。該電壓延遲 電路6之電壓延遲時間可透過改變該延遲電阻R21和延遲電 容C來進行調整，每次檢測完成後只要打開開關S，該放電 ®電阻R22即可釋放該延遲電容C之電壓，保證下次檢測之正 常進行。 該指示裝置2包括電阻R6〜R9、電位器R40、比較器 U2、雙極型電晶體Q2和發光二極體D2。 該電阻R6與電位器R40串聯於該穩定電壓VI與地之 間。調整該電位器R40，使該電阻R6與電位器R40間之節 點輸出一上限基準電壓，該上限基準電壓爲主機板電源提供 馨之電壓11之上限電壓。該比較器U2包括一正相輸入端、一 反相輸入端、一輸出端及一電源端，該比較器U2之反相輸 入端與該上限基準電壓連接，該比較器U2之正相輸入端透 過該電阻R7與主機板電源提供之電壓11連接，該比較器 U2之電源端與該電壓延遲電路6之場效電晶體Q8之第三端 連接。該比較器U2、電阻R8和R9、電晶體Q2及發光二極 體D2與該指示裝置1對應元件比較器U1、電阻R3和R4、 電晶體Q1及發光二極體D1之連接方式相同，於此不再贅 述。該發光二極體D2之陽極透過該電阻R5與該參考電壓 11 200844733 • V2連接。 . 當該主機板電源提供之電壓11小於該上限基準電壓 時，該比較器U2之輸出端輸出一低電平訊號，該電晶體Q2 之第一端接收該低電平訊號，故該電晶體Q2截止，從而該 發光二極體D2無電流流過而不發光。當該主機板電源提供 之電壓11大於該上限基準電壓時，該比較器U2之輸出端輸 出一高電平之控制訊號，該電晶體Q2之第一端接收該控制 訊號，故該電晶體Q2之第二端與第三端導通，從而該發光 ®二極體D2有電流流過而發出紅色光，指示該主機板電源提 供之電壓11異常。 該指示裝置3包括電阻R10〜R14、電位器R50、比較器 U3、雙極型電晶體Q3和發光二極體D3。 該電阻R10和電位器R50串聯於該穩定電壓VI與地之 間，調整該電位器R50,使該電阻R10與電位器R50間之節 點輸出一下限基準電壓等於主機板電源提供之電壓12之下 馨限電壓。該比較器U3之反相輸入端透過該電阻R11與主機 板電源提供之電壓12連接。該比較器U3之電源端與該電壓 延遲電路6之場效電晶體Q8之第三端連接。該指示裝置3 中比較器U3、電阻R12〜R14、電晶體Q3和發光二極體D3 之連接方式與該指示裝置1對應元件比較器U1、電阻 R3〜R5、電晶體Q1和發光二極體D1之連接方式相同，在此 不再贅述。 該指示裝置4包括電阻R15〜R18、電位器R60、比較器 U4、雙極型電晶體Q4和發光二極體D4。 12 200844733 - 該電阻R15與電位器R60串聯於該穩定電壓VI與地之 . 間，調整該電位器R60，使該電阻R15與電位器R60間之節 點輸出一上限基準電壓等於主機板電源提供之電壓12之上 限電壓。該比較器U4之正相輸入端透過該電阻R16與主機 板電源提供之電壓12連接。該比較器U4之電源端與該電壓 延遲電路6之場效電晶體Q8之第三端連接。該指示裝置4 中比較器U4、電阻R17和R18、電晶體Q4及發光二極體 D4之連接方式與該指示裝置2對應元件比較器U2、電阻R8 B和R9、電晶體Q2及發光二極體D2之連接方式相同，在此 不再贅述。 同樣，當該主機板電源提供之電壓12小於其下限電壓 時，該指示裝置3中之發光二極體D3發出紅色光，當該主 機板電源提供之電壓12大於其上限電壓時，該指示裝置4 中之發光二極體D4發出紅色光，指示該主機板電源提供之 電壓12異常。當該主機板電源提供之電壓12位於其上限電 馨壓與下限電壓之間，則該等發光二極體D3與D4均不發光。 該報警裝置5包括一發光二極體D5、一蜂鳴器B1、兩 雙極型電晶體Q5和Q6以及兩電阻R19和R20。該發光二 極體D5之陽極與該等發光二極體D1〜D4之陽極連接，該發 光二極體D5之陰極與該電晶體Q5之第一端連接，該電晶 體Q5之第二端透過該電阻R19與該參考電壓V2連接，該 電晶體Q6之第一端與該電晶體Q5之第二端連接，該蜂鳴 器B1之第一端透過該電阻R20與該參考電壓V2連接，該 蜂鳴器B1之第二端與該電晶體Q6之第二端連接，該等電 13 200844733 • 晶體Q5和Q6之第三端接地。 . 當主機板電源提供之電壓11或12出現異常時，該發光 二極體D5之陽極電壓等於該等發光二極體Dl、D2、D3或 D4之導通電壓，由於該發光二極體D5本身存在導通電壓， 故該發光二極體D5截止而不發光，該發光二極體D5之陰 極電壓等於零，該電晶體Q5截止，該電晶體Q6導通，該 蜂鳴器B1有電流流過而報警。當主機板電源提供之電壓11 和12都正常時，該發光二極體D5之陽極電壓爲高電平，該 B發光二極體D5導通而發出綠色光指示主機板電源提供之電 壓11和12都正常，同時該電晶體Q5導通，該電晶體Q6 截止，該蜂鳴器B1無電流流過而不報警。 由上述内容可知，監控人員可以根據該等發光二極體 D1〜D4是否發出紅色光來判斷主機板電源提供之電壓11和 12是正常還是過高或過低，如果主機板電源提供之電壓、1 和12有異常，則該發光二極體D5不發光並且該蜂鳴器B1 _報警。 由於該等發光二極體D1〜D4之陽極均連接在一起，故 能在該等指示裝置1〜4之間起隔離作用，不會因某一指示裝 置中之發光二極體導通而影響其他指示裝置中之發光二極 體之工作狀態。此外，該雙極型電晶體可以是其他之電子開 關，如場效電晶體。 綜上所述，本發明符合發明專利要件，爰依法提出專利 申請。惟，以上所述者僅為本發明之較佳實施例，舉凡熟悉 本案技藝之人士，在爰依本發明精神所作之等效修飾或變 14 200844733 • 化，皆應涵蓋於以下之申請專利範圍内。 .【圖式簡單說明】 圖1係本發明主機板電壓監控裝置的較佳實施方式的示 意圖。 【主要元件符號說明】 指示裝置 1、2、3、4 報警裝置 5 電壓 11、12 穩定電壓 VI 參考電壓 V2 電阻 R1 〜R20、R23 雙極性電晶體 Q1 〜Q6 比較器 U1 〜U4 發光二極體 D1 〜D5 蜂鳴器 B1 電位器 電壓延遲電路 R30、R40、R50、R60 6 延遲電容 C 場效電晶體 Q7、Q8 延遲電阻 R21 放電電阻 R22 開關 S * 15200844733 - IX. Description of the invention: [Technical Field] The present invention relates to a monitoring device, and more particularly to a power supply voltage monitoring device for a computer motherboard power supply and a voltage delay circuit thereof. [Prior Art] The power supply of the computer system consists of a primary power supply and a > primary power supply. ^ One power supply is the power supply of the chassis power output. The secondary power supply is the power output of each power conversion module on the motherboard. The power supply voltage of the chassis power output is +5V, -5V, +12V, -12V, +3.3V, etc. These voltages do not meet the requirements of each module on the motherboard, so the power conversion module needs to be added to the motherboard. The voltage of the chassis power output is converted into the working voltage of each module of the motherboard. For example, the working voltage of the CPU is 1.2V, and the working voltage of the north bridge is 1.5V and 1.2V. The power supplies that provide these working voltages are collectively referred to as secondary power sources. The motherboard manufacturer generally performs functional tests on the motherboard before the motherboard is shipped or put into use to ensure that the components of the motherboard are functioning properly. However, if the voltage output from the chassis power supply and the voltage output from the motherboard power conversion module are abnormal, then the functional test may cause an abnormal function test, which may result in burning of the parts and the circuit board. For example, if the voltage output from the motherboard to the CPU is too high, it will burn the CPU. If the voltage of the memory and the hard disk is high, the memory and the hard disk will be burned, which will not only cause economic loss. It also affects product quality and production efficiency. SUMMARY OF THE INVENTION In view of the above, it is necessary to provide a motherboard voltage monitoring device, before the functional test of the motherboard refers to whether the voltage provided by the motherboard power supply is 6 200844733, normal, and provides a voltage delay circuit to eliminate the voltage test The misjudgment caused by the power supply. A motherboard voltage monitoring device includes: a resistor and a potentiometer, the resistor and the potentiometer are connected in series between a stable voltage and a ground, and a node between them outputs a reference voltage; and a comparator includes a positive phase input a non-inverting input terminal, an output terminal and a power supply terminal, wherein a positive phase input terminal of the comparator is connected to a node between the resistor and the potentiometer, and an inverting input terminal of the comparator is provided with the power supply of the motherboard a voltage connection, when the voltage supplied by the power supply of the motherboard is less than the reference voltage, the output end of the comparator outputs a control signal; and an electronic switch includes first, second, and third ends, the electronic switch The first end is connected to the output end of the comparator, the second end is connected to a reference voltage, and the third end is grounded. When the first end of the electronic switch receives the control signal, the electronic switch is turned on; a cathode having a cathode connected to the second end of the electronic switch, an anode connected to the reference voltage, the LED being turned on when the electronic switch is turned on, and a voltage delay circuit connected to the body Reference voltage between a power supply terminal of the comparator ⑩ ratio after delaying the reference voltage to the comparator. A motherboard voltage monitoring device includes: a resistor and a potentiometer, the resistor and the potentiometer are connected in series between a stable voltage and a ground, and a node between them outputs a reference voltage; and a comparator includes a positive phase input An inverting input terminal, an output terminal and a power supply terminal, wherein the inverting input terminal of the comparator is connected to the node between the resistor and the potentiometer, and the positive phase input terminal of the comparator is provided with the power supply of the motherboard a voltage connection, when the voltage supplied by the motherboard power supply is greater than the reference voltage, the output end of the comparator outputs a control signal; an electric 7 200844733 sub-switch, including the first, second and third ends, the electronic The first end of the switch is connected to the output end of the comparator, the second end is connected to a reference voltage, and the third end is grounded. When the first end of the electronic switch receives the control signal, the electronic switch is turned on; a diode having a cathode connected to the second end of the electronic switch, an anode connected to the reference voltage, the LED being turned on when the electronic switch is turned on, and a voltage delay circuit, Connected between the reference voltage and the power supply terminal of the comparator, the reference voltage is delayed and then provided to the comparison. A voltage delay circuit includes a switch, a delay resistor, a delay capacitor, a discharge resistor, and a a second electronic switch and a third electronic switch, wherein the switch, the delay resistor and the delay capacitor are sequentially connected in series between the reference voltage and the ground, and the node between the delay resistor and the delay capacitor outputs a driving voltage, and the second electronic switch The first end is connected to the node, the second end is respectively connected with the reference voltage and the first end of the third electronic switch, the third end is grounded, and the second end of the third electronic switch is connected to the reference voltage, the third After the delay of the output of the terminal, the voltage is connected between the node and the ground, and the voltage of the delay capacitor is released after the switch is turned on. The motherboard voltage monitoring device causes the LED to emit light when the voltage supplied by the power supply of the motherboard is greater than or less than the reference voltage set by the monitoring personnel, thereby prompting the monitoring personnel to timely adjust the voltage provided by the power supply of the motherboard to avoid abnormal voltage. In the functional test, the expensive components are burned out. The above voltage delay circuit delays the operation of the comparator, ensuring that the test voltage has reached a stable value during the comparison, eliminating the misjudgment caused by the power supply timing. [Embodiment] 8 200844733 • Referring to FIG. 1, a preferred embodiment of the motherboard voltage monitoring device of the present invention is used to detect whether the voltages 11 and 12 provided by two different power supplies on the motherboard are normal before the function test of the motherboard. The motherboard voltage monitoring device includes four indicator devices 1 to 4, an alarm device 5, and a voltage delay circuit 6. The indicating devices 1 and 2 are used to indicate whether the voltage 11 provided by the power supply of the motherboard is normal. The indicating devices 3 and 4 are used to indicate whether the voltage 12 provided by the power supply of the motherboard is normal. The alarm device 5 is used to indicate the power of the motherboard. Whether the voltages 11 and 12 provided are normal and is reported as an alarm when the voltage supplied by the motherboard power supply is abnormal. The pointing device 1 includes resistors R1 to R5, a potentiometer R30, a comparator U1, a bipolar transistor Q1, and a light-emitting diode D1. The resistor R1 and the potentiometer 1130 are connected in series between a stable voltage of ¥1 and the ground. The stable voltage VI can be obtained by voltage regulation of a voltage supply of the chassis power supply. The potentiometer R30 is adjusted such that the node between the resistor R1 and the potentiometer R30 outputs a lower limit reference voltage which is the lower limit voltage of the voltage 11 supplied from the main board 0 power supply. The comparator U1 includes a positive phase input terminal, an inverting input terminal, an output terminal and a power terminal. The positive phase input terminal of the comparator U1 is connected to a node between the resistor R1 and the potentiometer R30. The comparator The inverting input terminal of U1 is connected to the voltage 11 provided by the power supply of the motherboard through the resistor R2, and the power terminal of the comparator U1 is connected to the voltage delay circuit 6. The transistor Q1 includes first, second, and third ends (ie, a base, a collector, and an emitter). The first end of the transistor Q1 is connected to the output end of the comparator U1 through the resistor R3. The two terminals are connected to a reference voltage 200844733 • V2 through the resistor R4, and the third terminal is grounded. The reference voltage V2 is one of the voltages of the chassis power supply. The cathode of the LED D1 is connected to the second end of the transistor Q1, and the anode thereof is connected to the reference voltage V2 through the resistor R5. The voltage delay circuit 6 includes a switch S, a delay resistor R21, a delay capacitor C, an N-channel field effect transistor Q7, and a P-channel field effect transistor Q8. The switch S, the delay resistor R21, and the delay capacitor C are sequentially Connected between the reference voltage V2 and the ground, the node between the delay resistor R21 and the delay capacitor C outputs a driving voltage, and a discharging resistor R22 is connected between the node and the ground; the first end of the field effect transistor Q7 (gate) connected to the node, the two ends (> and the pole) of the field effect transistor Q 7 are connected to the reference voltage V2 through a resistor R23 and to the first end of the field effect transistor Q8 ( a gate connection, the third end (source) of the field effect transistor Q7 is grounded; the second end (source) of the field effect transistor Q8 is connected to the reference voltage V2, and the field effect transistor Q8 is The three terminals (dip poles) are connected to the power terminal of the comparator U1. After the switch S is closed, the field effect transistor Q 7 is turned "on" when the voltage of the delay capacitor C rises to a certain value, thereby turning on the field effect transistor Q 8 . When the voltage 11 provided by the power supply of the motherboard is greater than the lower reference voltage, the output of the comparator U1 outputs a low level signal, and the first end of the transistor Q1 receives the low level signal, so the transistor Q1 As a result, the light-emitting diode D1 has no current flowing without emitting light. When the voltage 11 provided by the power supply of the motherboard is less than the lower reference voltage, the output of the comparator U1 outputs a high level control signal, and the first end of the transistor Q1 receives the control signal, so the transistor Q1 The second end is electrically connected to the third end, so that the light emitting diode D1 has a current flowing through it and emits red light 'refers to the power supply of the motherboard. 200844733. The voltage 11 is abnormal. Due to the timing problem of the power supply of the motherboard, when the voltage detection is performed, the voltage 11 provided by the power supply of the motherboard does not reach the stable value and is less than the lower reference voltage. Therefore, the voltage delay circuit 6 delays the reference voltage V2. Then, it is output to the comparator U1 to ensure that the voltage 11 provided by the power supply of the motherboard when the comparator U1 is operating has reached a stable value. The voltage delay time of the voltage delay circuit 6 can be adjusted by changing the delay resistor R21 and the delay capacitor C. After each detection is completed, the switch S can be released, and the discharge resistor R22 can release the voltage of the delay capacitor C to ensure that the voltage of the delay capacitor C is released. The next test is performed normally. The pointing device 2 includes resistors R6 to R9, a potentiometer R40, a comparator U2, a bipolar transistor Q2, and a light-emitting diode D2. The resistor R6 is connected in series with the potentiometer R40 between the stable voltage VI and ground. The potentiometer R40 is adjusted such that the node between the resistor R6 and the potentiometer R40 outputs an upper limit reference voltage which provides an upper limit voltage of the singular voltage 11 for the main board power supply. The comparator U2 includes a positive phase input terminal, an inverting input terminal, an output terminal and a power terminal. The inverting input terminal of the comparator U2 is connected to the upper limit reference voltage, and the positive phase input terminal of the comparator U2 The voltage of the comparator U2 is connected to the third terminal of the field effect transistor Q8 of the voltage delay circuit 6 through the resistor R7. The comparator U2, the resistors R8 and R9, the transistor Q2 and the light-emitting diode D2 are connected to the corresponding component comparator U1, the resistors R3 and R4, the transistor Q1 and the light-emitting diode D1 of the pointing device 1 in the same manner. This will not be repeated here. The anode of the LED D2 is connected to the reference voltage 11 200844733 • V2 through the resistor R5. When the voltage 11 provided by the power supply of the motherboard is less than the upper reference voltage, the output of the comparator U2 outputs a low level signal, and the first end of the transistor Q2 receives the low level signal, so the transistor Q2 is turned off, so that the light-emitting diode D2 has no current flowing without emitting light. When the voltage 11 provided by the power supply of the motherboard is greater than the upper reference voltage, the output of the comparator U2 outputs a high level control signal, and the first end of the transistor Q2 receives the control signal, so the transistor Q2 The second end and the third end are electrically connected, so that the light emitting diode diode D2 has a current flowing to emit red light, indicating that the voltage 11 provided by the power supply of the motherboard is abnormal. The pointing device 3 includes resistors R10 to R14, a potentiometer R50, a comparator U3, a bipolar transistor Q3, and a light-emitting diode D3. The resistor R10 and the potentiometer R50 are connected in series between the stable voltage VI and the ground, and the potentiometer R50 is adjusted so that the node between the resistor R10 and the potentiometer R50 outputs a lower limit reference voltage equal to the voltage 12 provided by the power supply of the motherboard. Xin limited voltage. The inverting input of the comparator U3 is connected to the voltage 12 provided by the main board power supply through the resistor R11. The power supply terminal of the comparator U3 is connected to the third terminal of the field effect transistor Q8 of the voltage delay circuit 6. The comparator U3, the resistors R12 to R14, the transistor Q3, and the light-emitting diode D3 of the pointing device 3 are connected to the component comparator U1, the resistors R3 to R5, the transistor Q1, and the light-emitting diode. The connection mode of D1 is the same and will not be described here. The pointing device 4 includes resistors R15 to R18, a potentiometer R60, a comparator U4, a bipolar transistor Q4, and a light-emitting diode D4. 12 200844733 - The resistor R15 and the potentiometer R60 are connected in series between the stable voltage VI and the ground, and the potentiometer R60 is adjusted so that the node between the resistor R15 and the potentiometer R60 outputs an upper limit reference voltage equal to that provided by the motherboard power supply. The upper limit voltage of voltage 12. The non-inverting input of the comparator U4 is coupled to the voltage 12 provided by the main board power supply through the resistor R16. The power supply terminal of the comparator U4 is connected to the third terminal of the field effect transistor Q8 of the voltage delay circuit 6. The comparator U4, the resistors R17 and R18, the transistor Q4 and the light-emitting diode D4 of the pointing device 4 are connected to the component comparator U2, the resistors R8 B and R9, the transistor Q2 and the light-emitting diode. The connection mode of the body D2 is the same, and will not be described again here. Similarly, when the voltage 12 provided by the power supply of the motherboard is less than the lower limit voltage, the LED D3 in the indicating device 3 emits red light, and when the voltage 12 provided by the power supply of the motherboard is greater than the upper limit voltage thereof, the indicating device The light-emitting diode D4 in 4 emits red light, indicating that the voltage supplied by the motherboard power supply 12 is abnormal. When the voltage 12 provided by the power supply of the motherboard is between the upper limit voltage and the lower limit voltage, the LEDs D3 and D4 do not emit light. The alarm device 5 includes a light-emitting diode D5, a buzzer B1, two bipolar transistors Q5 and Q6, and two resistors R19 and R20. The anode of the LED D5 is connected to the anodes of the LEDs D1 to D4, the cathode of the LED D5 is connected to the first end of the transistor Q5, and the second end of the transistor Q5 is The resistor R19 is connected to the reference voltage V2, the first end of the transistor Q6 is connected to the second end of the transistor Q5, and the first end of the buzzer B1 is connected to the reference voltage V2 through the resistor R20. The second end of the buzzer B1 is connected to the second end of the transistor Q6. The isoelectric 13 200844733 • The third ends of the crystals Q5 and Q6 are grounded. When the voltage 11 or 12 provided by the power supply of the motherboard is abnormal, the anode voltage of the LED D5 is equal to the conduction voltage of the LEDs D1, D2, D3 or D4, due to the LED D5 itself There is a turn-on voltage, so that the light-emitting diode D5 is turned off and does not emit light, the cathode voltage of the light-emitting diode D5 is equal to zero, the transistor Q5 is turned off, the transistor Q6 is turned on, and the buzzer B1 has a current flowing through the alarm. . When the voltages 11 and 12 provided by the power supply of the motherboard are normal, the anode voltage of the LED D5 is at a high level, and the B LED L5 is turned on to emit green light to indicate the voltages 11 and 12 provided by the power supply of the motherboard. Both are normal, and the transistor Q5 is turned on, the transistor Q6 is turned off, and the buzzer B1 has no current flowing without alarm. It can be seen from the above that the monitoring personnel can judge whether the voltages 11 and 12 provided by the power supply of the motherboard are normal or too high or too low according to whether the LEDs D1 to D4 emit red light, if the voltage supplied by the power supply of the motherboard, If there is an abnormality in 1 and 12, the light-emitting diode D5 does not emit light and the buzzer B1_alarm. Since the anodes of the LEDs D1 to D4 are connected together, the isolation between the indicating devices 1 to 4 can be prevented, and the LEDs in a certain indicating device are not affected. Indicates the operating state of the light-emitting diode in the device. In addition, the bipolar transistor can be other electronic switches, such as field effect transistors. In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and those skilled in the art will be able to cover the following claims within the scope of the present invention. Inside. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic illustration of a preferred embodiment of a motherboard voltage monitoring device of the present invention. [Main component symbol description] Indication device 1, 2, 3, 4 Alarm device 5 Voltage 11, 12 Stable voltage VI Reference voltage V2 Resistor R1 ~ R20, R23 Bipolar transistor Q1 ~ Q6 Comparator U1 ~ U4 LED D1 ~ D5 Buzzer B1 Potentiometer voltage delay circuit R30, R40, R50, R60 6 Delay capacitor C Field effect transistor Q7, Q8 Delay resistor R21 Discharge resistor R22 Switch S * 15